Not sure what to do about bi-girlfriend
So I don't know what to think an I am so confused. I have been with my girlfriend for going on 6 months, an now she tells me she's bi. I try to talk to her about how I feel about it but she gets upset an says its because I don't understand. I can't if she won't talk to me about it, its just that I don't really like the idea of my girl off doing what not with another person. But I don't know, few people I talked to consider it cheating, but I don't know the more I think about it the more I think it. What can I say or do, I don't know...